A basic model for describing plasma dynamics is given by the Euler-Maxwell system, in which compressible ion and electron fluids interact with their own self-consistent electromagnetic field. In this paper we consider the "one-fluid" Euler-Maxwell model for electrons, in 2 spatial dimensions, and prove global stability of a constant neutral background.In 2 dimensions our global solutions have relatively slow (strictly less than 1/t) pointwise decay and the system has a large (codimension 1) set of quadratic time resonances. The issue in such a situation is to solve the "division problem". To control the solutions we use a combination of improved energy estimates in the Fourier space, an L 2 bound on an oscillatory integral operator, and Fourier analysis of the Duhamel formula.
YU DENG, ALEXANDRU D. IONESCU, AND BENOIT PAUSADERGuo-Ionescu-Pausader [23] (small irrotational perturbations of constant solutions), following earlier partial results in simplified models in [22,25,18,30]. See also the introduction of [23] for a longer discussion of the Euler-Maxwell system in 3D, and its connections to many other models in mathematical physics, such as the Euler-Poisson model, the Zakharov system, the KdV, and the NLS.A simplification of the full system is the "one-fluid" model, which accounts for the interaction of electrons and the electromagnetic field, but neglects the dynamics of the ion fluid. Under suitable irrotationality assumptions, this model can be reduced to a coupled system of two Klein-Gordon equations with different speeds and no null structure. While global results are classical in the case of scalar wave and Klein-Gordon equations, see for example [33,34,36,37,38,39,9,10,42,44,14,15,2,3,4,5], it was pointed out by Germain [17] that there are key new difficulties in the case of two Klein-Gordon equations with different speeds. In this case, the classical vector-field method does not seem to work well, and there are large sets of resonances that contribute in the analysis.The one-fluid Euler-Maxwell model in 3D was analyzed in [18], using the "space-time resonance method", and the authors proved global existence and scattering, with weak decay like t −1/2 . A more robust result for this problem, which gives time-integrability of the solution in L ∞ , for all parameters, was obtained by two of the authors in [30].In this paper we consider the one-fluid Euler-Maxwell model 1 in 2D. As in dimension 3, in the irrotational case this can still be reduced to a quasilinear coupled system of two Klein-Gordon equations with different speeds and no null structure. At the analytical level, one has, of course, all the difficulties of the 3D problem, such as large sets of resonances. In addition, there is one critical new difficulty, namely the slow decay of solutions, as it was observed by Bernicot-Germain [6] that the nonlinear solutions cannot have the "almost" integrable 1/t decay, due to strong resonant quadratic interactions. This slow decay and the presence of large sets of resonances require new ideas to contro...